1. Field of the Invention
The present invention relates to a flight control system for controlling a flight of an aircraft. More particularly, the present invention is concerned with a flight control system including an actuator control computer and a flight control computer.
2. Description of the Related Art
Up until now, there has been proposed a wide variety of flight control systems for controlling a flight of an aircraft. One typical example of the conventional flight control system is known as Fly By Wire System, hereinlater simply referred to as xe2x80x9cFBWxe2x80x9d system, which enables to control an actuator actuating flight control surfaces, for example, ailerons, by means of electric signals. The conventional flight control system 1100 is exemplified and shown in FIG. 2 as comprising an actuator control computer 1300, hereinlater simply referred to as xe2x80x9cACCxe2x80x9d, a flight control computer 1200, hereinlater simply referred to as xe2x80x9cFCCxe2x80x9d, and an actuator 1400.
The FCC 1200 is operative to receive an operational instruction 1500a from a pilot and a state signal 1500b indicative of the state of the aircraft from the aircraft, and generate an instruction signal 1100a to operate the actuator 1400 of the aircraft. The actuator 1400 is operative to actuate the flight control surfaces and output a feedback signal 1400a in return. The ACC 1300 is operative to receive the instruction signal 1100a from the FCC 1200 and the feedback signal 1400a from the actuator 1400 to generate an actuator control signal 1100b on the basis of the instruction signal and the feedback signal thus received.
Furthermore, the conventional flight control system 1100 employs various fault detections to prevent failures from occurring in the FCC 1200 and the ACC 1300 because of the fact that the conventional flight control system 1100 is required to accurately control a flight of an aircraft. A processor or software is subjected to failures such as, for example, a failure randomly occurring, hereinlater simply referred to as xe2x80x9crandom failuresxe2x80x9d. The FCC 1200 may comprise, for example, a plurality of FCC microprocessors identical in design and software with one another and have a plurality of FCC microprocessors respectively generate a plurality of instruction signals 1100a to detect random failures occurring in the processor or software. A processor or software is subjected to another failure consequently occurring due to the characteristics inherent in the processor or software, hereinlater simply referred to as xe2x80x9cgeneric failuresxe2x80x9d. The FCC 1200 may comprise, for example, a plurality of FCC microprocessors different in design and software from one another and have a plurality of FCC microprocessors respectively generate a plurality of instruction signals 1100a to detect generic failures occurring in the processor or software. While it has been described in the above that the FCC 1200 may comprise a plurality of FCC microprocessors to detect random and generic failures, it is needless to mention that the ACC 1300 may comprise a plurality of ACC microprocessors to detect random and generic failures in the same manner.
The conventional flight control system 1100, however, encounters a drawback that the conventional flight control system 1100 is required to comprise, for example, a plurality of ACC microprocessors different in design and software from one another and have a plurality of ACC microprocessors respectively generate a plurality of instruction signals 100a to detect generic failures consequently occurring due to the characteristics inherent in the ACC microprocessor or software related to the ACC microprocessor. This leads to the fact that the conventional flight control system 1100 requires suppliers to develop and produce a plurality of microprocessors different from one another in design and a plurality of software different from one another in design in order to detect generic failures due to the characteristics inherent in the processor or software, thereby making it difficult for the suppliers to reduce the development and manufacturing costs. The present invention contemplates resolution of such problem.
It is therefore an object of the present invention to provide a flight control system, which does not require suppliers to develop and produce a plurality of ACC processors 320 different from one another in design and software in order to detect failures, thereby making it possible for the suppliers to reduce the development and manufacturing costs while enabling to detect generic failures consequently occurring due to the characteristics inherent in the ACC processor or software related to the ACC processor.
It is another object of the present invention to provide a flight control system, which does not require suppliers to develop and produce a plurality of ACC processors 320 different from one another in design and software in order to detect failures, thereby making it possible for the suppliers to reduce the development and manufacturing costs while enabling to prevent an actuator from being controlled by failed ACC.
In accordance with a first aspect of the present invention, there is provided a flight control system for controlling a flight of an aircraft, comprising: an actuator for actuating flight control surfaces; a flight control computer for operating the actuator; and an actuator control computer for controlling the operation of the actuator. The flight control computer comprises: an FCC processor for generating an instruction signal to operate the actuator on the basis of an operational instruction signal inputted from a pilot and a state signal indicative of the state of an aircraft, a reference signal on the basis of the instruction signal and a feedback signal from the actuator. The actuator control computer comprises: an ACC processor for generating an actuator control signal on the basis of the instruction signal generated by the FCC processor and the feedback signal from the actuator, and a servo amplifier for amplifying the actuator control signal generated by the ACC processor to be outputted to the actuator. The actuator is operative to actuate the flight control surfaces in accordance with the actuator control signal amplified by the servo amplifier. In the aforesaid flight control system, the flight control computer further comprises: a comparing section for comparing the actuator control signal generated by the ACC processor with the reference signal generated by the FCC processor to detect a failure. The FCC processor is different in design from the ACC processor. In the aforesaid flight control system, the FCC processor may generate the reference signal in accordance with FCC software. The ACC processor may generate the actuator control signal in accordance with ACC software. The FCC software may be different from the ACC software in design.
In accordance with a second aspect of the present invention, there is provided a flight control system for controlling a flight of an aircraft, comprising: an actuator for actuating flight control surfaces; a flight control computer for operating the actuator; and an actuator control computer for controlling the operation of the actuator. The flight control computer comprises: an FCC processor for generating an instruction signal to operate the actuator on the basis of an operational instruction signal inputted from a pilot and a state signal indicative of the state of an aircraft, a reference signal on the basis of the instruction signal and a feedback signal from the actuator. The actuator control computer comprises: an ACC processor for generating an actuator control signal on the basis of the instruction signal generated by the FCC processor and the feedback signal from the actuator, and a servo amplifier for amplifying the actuator control signal generated by the ACC processor to be outputted to the actuator. The actuator is operative to actuate the flight control surfaces in accordance with the actuator control signal amplified by the servo amplifier. In the aforesaid flight control system, the flight control computer further comprises: a comparing section for comparing the actuator control signal generated by the ACC processor with the reference signal generated by the FCC processor to detect a failure. The FCC processor is operative to generate the reference signal in accordance with FCC software. The ACC processor is operative to generate the actuator control signal in accordance with ACC software. The FCC software is different from the ACC software in design.
In the aforesaid flight control system, the FCC processor may receive the feedback signal from the actuator not through the ACC processor. The comparing section may receive the actuator control signal generated by the ACC processor not through the ACC processor.
In accordance with a third aspect of the present invention, the FCC processor comprises: an instruction signal generating section for generating an instruction signal to operate the actuator on the basis of an operational instruction signal inputted from a pilot and a state signal indicative of the state of an aircraft, and a reference signal generating section for generating a reference signal on the basis of the instruction signal generated by the instruction signal generating section and a feedback signal from the actuator. The comparing section is operative to compare the actuator control signal generated by the ACC processor with the reference signal generated by the reference signal generating section to detect a failure.
In accordance with a fourth aspect of the present invention, the actuator control computer further comprises: a digital analog converter for converting the actuator control signal generated by the ACC processor from digital to analog format to be outputted to the servo amplifier and the FCC processor. The servo amplifier is operative to amplify the actuator control signal in analog format converted by the digital analog converter to be outputted to the actuator. The comparing section is operative to compare the actuator control signal in analog format converted by the digital analog converter with the reference signal generated by the FCC processor to detect a failure.
In the aforesaid flight control system, the actuator control computer may further comprise a control prevention section for preventing the actuator from being controlled by the actuator control computer. The comparing section may compare the actuator control signal generated by the ACC processor with the reference signal generated by the FCC processor to generate a control prevention signal in accordance with the result of the comparison, and the control prevention section may prevent the actuator from being controlled by the actuator control computer in response to the control prevention signal generated by the comparing section. The comparing section may output the control prevention signal to the control prevention section not through the ACC processor. The comparing section may form part of the FCC processor.
The aforesaid flight control system may further comprise a data bus for connecting the actuator control computer with the flight control computer so that the actuator control computer is operative to receive the instruction signal and the control prevention signal from the flight control computer and transmit the actuator control signal and the feedback signal to the flight control computer.